This invention relates to a luminous display unit e.g., a luminous display unit using a self light emitting element such as an organic electroluminescence element (OLED), a fluorescent display tube, a light emitting diode (LED), etc.
As shown in FIG. 5, an OLED 5 has at least an anode 2 constructed by a transparent electroconductive material such as indium, tin, oxide (ITO), etc., an organic layer 3 constructed by one or more layers (constructed by at least a single layer structure of an organic light emitting layer, or a multilayer structure in which a positive hole injecting layer, a positive hole transport layer, an electronic transport layer and an electronic injecting layer, etc. are laminated and formed from an anode side in accordance with the organic light emitting layer), and a cathode 4 constructed by a metallic electroconductive material such as aluminum (Al), etc. on a transparent substrate 1. For example, this OLED 5 is known in Japanese Patent Publication No. 32307/1994. The OLED 5 can emit light in a predetermined desirable pattern by shapes of the anode 2 and the cathode 4. Further, it is possible to perform display in constant electric current driving from a direct current power source vcc from several volts to several ten volts.
When a luminous display unit 100 using such an OLED 5 is utilized as a digital type distance recorder of a display unit for a vehicle, as shown in FIG. 6, the anode 2 is divided into seven segments 2a to 2g arranged in an 8-shape so that Arabic numerals xe2x80x9c0xe2x80x9d to xe2x80x9c9xe2x80x9d are artificially displayed. Numerals of plural digits can be displayed by arranging a plurality of such anodes in a transversal direction. For example, such a construction is known in Japanese Patent Laid-Open No. 106887/1997.
FIG. 6 shows an example of six-digit display able to display xe2x80x9c000000xe2x80x9d to xe2x80x9c999999xe2x80x9d.
It is known that light emitting intensity in each of the segments 2a to 2g is reduced in accordance with a light emitting time. For example, when the light emitting time is ten thousand hours, light emitting luminance is reduced to about 50% of the original light emitting luminance.
If each of the segments 2a to 2g emits light for a uniform light emitting time, the reductions in light emitting luminance are uniform. Therefore, no difference in light emitting luminance between the respective segments 2a to 2g is almost caused irrespective of the length of a using time of the luminous display unit.
However, when there is a large difference in light emitting time, the difference in light emitting luminance is increased. Accordingly, as the using time of the luminous display unit is lengthened, this difference is enlarged. When these segments 2a to 2g simultaneously emit light, there is a case in which a feeling of physical disorder is felt by the difference in light emitting luminance. In such a state, goods property is greatly damaged.
In the case of the digital type distance recorder, light emitting frequency of each of the segments 2a to 2g in the display of numerals xe2x80x9c0xe2x80x9d to xe2x80x9c9xe2x80x9d of ten kinds in each digit is provided as shown in FIG. 7. In FIG. 7, the segment 2c has a maximum light emitting frequency of nine times, and the segment 2e has a minimum light emitting frequency of four times. When it is supposed that the light emitting time of each of the numerals xe2x80x9c0xe2x80x9d to xe2x80x9c9xe2x80x9d is uniform, the light emitting time of the segment 2c is 2.25 times the light emitting time of the segment 2e. 
Accordingly, although it is the same digit, the light emitting luminance of the segment 2c is rapidly reduced in comparison with the light emitting luminance of the segment 2e. When this difference in light emitting luminance is increased to such an extent that this difference can be recognized, a problem exists in that a user has a feeling of physical disorder. When the difference in light emitting luminance is equal to or greater than a value corresponding to 30% of a higher light emitting luminance among these light emitting luminances, it is confirmed by an experiment of the present inventors, etc. that the difference in light emitting luminance between both the segments can be recognized.
When no numeral xe2x80x9c0xe2x80x9d is displayed on an upper digit side, i.e., when xe2x80x9c120xe2x80x9d having no numerals xe2x80x9c0xe2x80x9d in upper three digits is displayed as a blank display instead of xe2x80x9c000120xe2x80x9d displaying numerals xe2x80x9c0xe2x80x9d in the upper three digits in display of the numeral xe2x80x9c120xe2x80x9d (in the case of a so-called leading zero suppress display), the light emitting time in the upper digit is shortened in comparison with a lower digit so that a problem similar to the above problem is caused.
The present invention resides in a luminous display unit having plural light emitting portions by using a self light emitting element reduced in light emitting luminance in accordance with a light emitting time and having differences in light emitting time in their light emitting portions, and characterized in that, when a light emitting mode in said light emitting portions is regularly determined, said light emitting time is presumed from light emitting frequencies of said light emitting portions calculated from said light emitting mode, and the light emitting luminances are set to be different from each other from the first in a light emitting portion having a large light emitting frequency and a light emitting portion having a small light emitting frequency at a using time of said luminous display unit so as not to recognize a difference in light emitting luminance caused between both the light emitting portions at said using time. For example, each of luminous display units 100, 110 has plural segments 21a to 21g (light emitting portions) by using an OLED (a self light emitting element) reduced in light emitting luminance in accordance with a light emitting time and has differences in light emitting time in their light emitting portions. When a light emitting mode in the segments 21a to 21g is regularly determined, the light emitting time of each of the segments 21a to 21g is presumed from light emitting frequencies of the segments 21a to 21g calculated from this light emitting mode, and the light emitting luminances are set to be different from each other from the first in a light emitting portion having a large light emitting frequency and a light emitting portion having a small light emitting frequency at a using time of each of the luminous display units 100, 110 so as not to recognize a difference in light emitting luminance caused between both the light emitting portions at the using time. Thus, the generation of a large difference in light emitting luminance of each of the segments 21a to 21g is prevented at the using time of each of the luminous display units 100, 110 so that goods property can be maintained.
The present invention also resides in a luminous display unit having plural light emitting portions by using a self light emitting element reduced in light emitting luminance in accordance with a light emitting time and having differences in light emitting time in their light emitting portions, and characterized in that, when a light emitting mode in said light emitting portions is regularly determined, said light emitting time is presumed from light emitting frequencies of said light emitting portions calculated from said light emitting mode, and the light emitting luminances are set to be different from each other from the first in a light emitting portion having a large light emitting frequency and a light emitting portion having a small light emitting frequency at a using time of said luminous display unit such that a difference in light emitting luminance caused between both the light emitting portions lies within 30% of a high light emitting luminance among the light emitting luminances at said using time. For example, each of luminous display units 100, 110 has plural segments 21a to 21g (light emitting portions) by using an OLED (a self light emitting element) reduced in light emitting luminance in accordance with a light emitting time and has differences in light emitting time in their light emitting portions. When a light emitting mode in the segments 21a to 21g is regularly determined, the light emitting time of each of the segments 21a to 21g is presumed from light emitting frequencies of the segments 21a to 21g calculated from this light emitting mode, and the light emitting luminances are set to be different from each other from the first in a light emitting portion having a large light emitting frequency and a light emitting portion having a small light emitting frequency at a using time of each of the luminous display units 100, 110 such that a difference in light emitting luminance caused between both the light emitting portions lies within 30% of a high light emitting luminance among the light emitting luminances at said using time. Thus, the generation of a large difference in light emitting luminance of each of the segments 21a to 21g is prevented at the using time of each of the luminous display units 100, 110 so that goods property can be maintained.
The present invention also resides in a luminous display unit having plural light emitting portions by using a self light emitting element reduced in light emitting luminance in accordance with a light emitting time and having differences in light emitting time in their light emitting portions, and characterized in that, when a light emitting mode in said light emitting portions is regularly determined, said light emitting time is presumed from light emitting frequencies of said light emitting portions calculated from said light emitting mode, and the light emitting luminance of a light emitting portion having a small light emitting frequency is set to be lower than that of a light emitting portion having a large light emitting frequency from the first with respect to the light emitting portion having a large light emitting frequency and the light emitting portion having a small light emitting frequency at a using time of said luminous display unit such that a difference in light emitting luminance caused between both the light emitting portions lies within 30% of a high light emitting luminance among the light emitting luminances at said using time. For example, each of luminous display units 100, 110 has plural segments 21a to 21g (light emitting portions) by using an OLED (a self light emitting element) reduced in light emitting luminance in accordance with a light emitting time and has differences in light emitting time in their light emitting portions. When a light emitting mode in the segments 21a to 21g is regularly determined, the light emitting time of each of the segments 21a to 21g is presumed from light emitting frequencies of the segments 21a to 21g calculated from this light emitting mode, and the light emitting luminance of a light emitting portion having a small light emitting frequency is set to be lower than that of a light emitting portion having a large light emitting frequency from the first with respect to the light emitting portion having a large light emitting frequency and the light emitting portion having a small light emitting frequency at a using time of each of the luminous display units 100, 110 such that a difference in light emitting luminance caused between both the light emitting portions lies within 30% of a high light emitting luminance among the light emitting luminances at said using time. Thus, the generation of a large difference in light emitting luminance of each of the segments 21a to 21g is prevented at the using time of each of the luminous display units 100, 110 so that goods property can be maintained.
The present invention also resides in a luminous display unit having plural light emitting portions by using a self light emitting element reduced in light emitting luminance in accordance with a light emitting time and having differences in light emitting time in their light emitting portions, and characterized in that the light emitting luminance of a light emitting portion having a long light emitting time and the light emitting luminance of a light emitting portion having a short light emitting time at a using time of said luminous display unit are set to be different from each other from the first so as not to recognize a difference in light emitting luminance caused between both the light emitting portions at said using time. For example, each of luminous display units 100, 110 has plural segments 21a to 21g (light emitting portions) by using an OLED (a self light emitting element) reduced in light emitting luminance in accordance with a light emitting time and has differences in light emitting time in their light emitting portions. The light emitting luminance of a light emitting portion having a long light emitting time and the light emitting luminance of a light emitting portion having a short light emitting time at a using time of each of the luminous display units 100, 110 are set to be different from each other from the first so as not to recognize a difference in light emitting luminance caused between both the light emitting portions at said using time. Thus, the generation of a large difference in light emitting luminance of each of the segments 21a to 21g is prevented at the using time of each of the luminous display units 100, 110 so that goods property can be maintained.
The present invention also resides in a luminous display unit having plural light emitting portions by using a self light emitting element reduced in light emitting luminance in accordance with a light emitting time and having differences in light emitting time in their light emitting portions, and characterized in that the light emitting luminance of a light emitting portion having a long light emitting time and the light emitting luminance of a light emitting portion having a short light emitting time at a using time of said luminous display unit are set to be different from each other from the first such that a difference in light emitting luminance caused between both the light emitting portions lies within 30% of a high light emitting luminance among the light emitting luminances at said using time. For example, each of luminous display units 100, 110 has plural segments 21a to 21g (light emitting portions) by using an OLED (a self light emitting element) reduced in light emitting luminance in accordance with a light emitting time and has differences in light emitting time in their light emitting portions. The light emitting luminance of a light emitting portion having a long light emitting time and the light emitting luminance of a light emitting portion having a short light emitting time at a using time of each of the luminous display units 100, 110 are set to be different from each other from the first such that a difference in light emitting luminance caused between the light emitting portions lies within 30% of a high light emitting luminance among the light emitting luminances at said using time. Thus, the generation of a large difference in light emitting luminance of each of the segments 21a to 21g is prevented at the using time of each of the luminous display units 100, 110 so that goods property can be maintained.
Further, the present invention resides in a luminous display unit having plural light emitting portions by using a self light emitting element reduced in light emitting luminance in accordance with a light emitting time and having differences in light emitting time in their light emitting portions, and characterized in that the light emitting luminance of a light emitting portion having a short light emitting time is set to be lower than that of a light emitting portion having a long light emitting time from the first with respect to the light emitting portion having a long light emitting time and the light emitting portion having a short light emitting time at a using time of said luminous display unit such that a difference in light emitting luminance caused between both the light emitting portions lies within 30% of a high light emitting luminance among the light emitting luminances at said using time. For example, each of luminous display units 100, 110 has plural segments 21a to 21g (light emitting portions) by using an OLED (a self light emitting element) reduced in light emitting luminance in accordance with a light emitting time and has differences in light emitting time in their light emitting portions. The light emitting luminance of a light emitting portion having a short light emitting time is set to be lower than that of a light emitting portion having a long light emitting time from the first with respect to the light emitting portion having a long light emitting time and the light emitting portion having a short light emitting time at a using time of each of the luminous display units 100, 110 such that a difference in light emitting luminance caused between both the light emitting portions lies within 30% of a high light emitting luminance among the light emitting luminances at said using time. Thus, the generation of a large difference in light emitting luminance of each of the segments 21a to 21g is prevented at the using time of each of the luminous display units 100, 110 so that goods property can be maintained.
The luminous display unit is particularly characterized in that said self light emitting element is an organic electroluminescence element. For example, in the case of the OLED as a light emitting element, a change in light emitting luminance according to the light emitting time (light emitting frequency) is notable, and the generation of a large difference in light emitting luminance of each of the segments 21a to 21g is prevented at the using time of each of the luminous display units 100, 110 so that goods property can be maintained.
The luminous display unit is particularly characterized in that said luminous display unit is a display unit for a vehicle displaying a numeral of plural digits. For example, in the case of the display unit for a vehicle displaying a numeral of plural digits as the luminous display units 100, 110, the change in light emitting luminance is notable since it is expected that the display unit is used for a long period such as several hundred thousand Km or several years. In this case, the generation of a large difference in light emitting luminance of each of the segments 21a to 21g is also prevented at the using time of each of the luminous display units 100, 110 so that goods property can be maintained.